The present invention relates to sensing devices. In particular, the invention relates to sensing devices utilizing a composite diaphragm in which nanotubes or nanowires are embedded or sandwiched between high dielectric or insulating thin films.
Recent discoveries of nanoscale materials have generated great interest from a technological point of view. Carbon nanotubes (CNT) have attracted attention due to their mechanical, electrical, and thermal properties. Numerous applications of carbon nanotube technology for sensing pressure, temperature, gases, and other parameters have been proposed, using a number of different sensing mechanisms. Semiconducting nanowires of material such as silicon, gallium arsenide, and indium phosphide have been developed, and also have drawn attention for potential sensing applications.
Proposed sensors using carbon nanotubes or semiconducting nanowires are found in the following articles: John Liu, “Design, Fabrication, and Testing of Piezoresistive Pressure Sensors Using Carbon Nanotubes”, Stanford Nanofabrication Facility (2002); Takao Someya et al., “Alcohol Vapor Sensors Based On Single-Walled Carbon Nanotube Field Effect Transistors” Nano Letters Vol. 3, No. 7, 877-881 (2003); Tsu-Wei Chou et al., “Nanomechanical Sensors Based On Carbon Nanotube Arrays”, NSF Nanoscale Science and Engineering Grantess Conference, Dec. 16-18, 2003; Paolo Lugli, “Plastronics molecular, organic and biological electronics: an overview: Micro-Nano Technologies for Space, May 2003; Jian Wu, “Computational Design Of Carbon Nanotube Electromechanical Pressure Sensors” The American Physical Society (2004); Alexander Star et al., “Nanoelectronic Carbon Dioxide Sensors”, Advanced Materials 16, No. 22, pages 2049-2052 (2004); Randal J. Grow et al. “Piezoresistance Of Carbon Nanotubes On Deformable Thin-Film Membranes” Applied Physics Letters (2005); Progress Report for ITAS MSFT “Nanoscale Devices and Material Integration: Carbon Nanotube Based Materials for NDE”, April, 2005; Prof. Feng Liu, Computational R&D for Industrial Applications, Center for High-Performance Computing, Fall, 2005; Danvers E. Johnston et al., “Electronic Devices Based on Purified Carbon Nanotubes Grown By High Pressure Decomposition of Carbon Monoxide”, Feb. 7, 2005; C. Stampfer et al. “Fabrication of Single-Walled Carbon-Nanotube-Based Pressure Sensors” (2006); Professor Dr. Christofer Hierold “FEM Simulations On Single-Walled Carbon Nanotube Based Pressure Sensor Systems” Mikro-Und Nanostysteme (2006); Chunyu Li “Atomistic Modeling Of Carbon Nanotube-Based Mechanical Sensors” Journal of Intelligent Material Systems and Structures, Vol. 17, No. 3, 247-254 (2006); In-Mook Choi et al., “Development Of Low Pressure Sensor Based On Carbon Nanotube Field Emission” Metrologia (2006); Sinha et al., “Carbon Nanotube-Based Sensors”, Ingentaconnect (2006); NASA, “Nanoscale Mass Transport and Carbon Nanotube Based Membranes” (2006).
Sensors using nanotubes or nanowires are also described in Jin U.S. Pat. No. 6,286,226 and Miyajima et al. U.S. Pat. No. 6,848,320, and in Chen et al. Patent Application Publication US 2004/0001778, Kurtz Patent Application Publication US 2004/0188780, and Gokturk Patent Application Publication US 2005/0036905.